In order to increase the breakdown voltage of a vertical type semiconductor device, a termination structure can be used to relax an electric field. As such a termination structure, a JTE (Junction Termination Extension), a FLR (Field limiting Ring) (also referred to as “guard ring”), and the like have been known. For example, according to Shiro Hino et al., “SiC-MOSFET structure enabling fast turn-on and -off switching”. Material Science Forum. Vols 717-720 (2012), pp 1097-1100 (Non-Patent Document 1), in an n channel double implantation MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an outer circumferential p well is provided in a silicon carbide substrate. The outer circumferential p well is covered with a field oxide film (insulating film).